On Tue, 2014-05-13 at 03:12 +0000, Li, Elvin wrote: > David, > Where do we initialize > UmaAddress/UmaSize/HiPermanentMemoryAddress/HiPermanentMemorySize? > And could you explain the purpose of these new fields? > > Thanks > Elvin
Hi Elvin, These fields are defined in the v0.98 update to the CSM specification, available at http://www.intel.com/content/www/us/en/architecture-and-technology/unified-extensible-firmware-interface/efi-compatibility-support-module-specification-v098.html The UmaAddress and UmaSize fields allow a CSM to use memory between 0xc0000 and 0xfffff as RAM, instead of having it marked read-only by the LegacyRegion implementation on the UEFI side. Some implementations, such as SeaBIOS, want to put stacks there to avoid overflowing a low-memory application/OS stack. The HiPermanentMemoryAddress/Size fields are to allow permanent allocations in high memory that doesn't needlessly fragment the memory map. Current implementation in the wild have been seen putting PCIBIOS high allocations in stupid places, mostly because the UEFI side doesn't give them a *sane* location to allocate from. I haven't yet implemented this on the UEFI side; just put the fields into the header file. See the specification update for details of how the fields are updated and interpreted in various combinations of updated/non-updated CSM/UEFI. -- David Woodhouse Open Source Technology Centre david.woodho...@intel.com Intel Corporation
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